Contemporary accelerator technology is based on radio frequency (rf) electromagnetic waves in vacuum tubes [ref. 1, Livingston]. This technology served well for high energy physics as well as other applications such as medical therapy machines for several decades. However, in recent decades it has become apparent that the so-called Livingston chart, in which the accelerator energies exponentially increase over time (just like Moore's law in the semiconductor chip capabilities) [ref. 1], tends to show slower growth (and even saturation tendency). This is due to the accelerating gradient in rf accelerators having a limit beyond which the metallic surface of the rf tube begins to spark and the metal breaks down to create plasma inside the vacuum tube. A typical limit for such an accelerating gradient is about 100 MeV/m.
A laser wakefield accelerator (LWFA) [ref. 2] and its derivatives, such as plasma wakefield accelerators [ref. 2a], use the broken-down gas, plasma, as the medium of acceleration. Thus, the LWFA cannot further break down and has an accelerating gradient far greater than conventional rf accelerators. The typical accelerating gradient of an LWFA is about 100 GeV/m (and other plasma wakefield accelerators are about 1-10 GeV/m), which is about four orders of magnitude greater than the existing rf accelerators.
With the advent of new laser technology called the Chirped Pulse Amplification (CPA) [ref. 3], the accelerating gradient of LWFAs has been scientifically verified many times over [ref. 4]. As predicted, a typical acceleration gradient of 100 GeV/m and a typical energy gain of 1 GeV over a few cm have been observed. The theoretical energy gain is also seen to scale with the inverse of the density of the acceleration medium. The decrease of the plasma density needs to be accompanied by the increase of the laser energy. Thus, in order to increase the gained energy in LWFAs from GeV to 100 GeV, the laser energy needs to increase from J to 100-1000 J class.
Thus, it is desirable to provide systems and methods that facilitate high energy acceleration in wakefield accelerators.